Micrometer apparatus



June 26, 1962 J. M. I Ewls MICROMETER APPARATUS Filed June 2, 1958 5Sheets-Sheet 1 June 26, 1962 J. M. |:w|s

MICROMETER APPARATUS 3 Sheets-Sheet 2 Filed June 2, 1958 y HM W550/*pgsJune 26, 1962 J. M. LEWIS MICROMETER APPARATUS 3 Sheets-Sheet 3 FiledJune 2, 1958 1.. j A.. o l Aww n n- I... n ----1 1--..,--- .,A. .Hw...HN |||1 l l e 1| l- 1-- I- T.

d x ev Q s., m5 d x N d w SQ QN. .5m

M ll I|||v.......`1...`|| lxln 1. x SS s v NN o [fn/@17 'or'. John/V.Lew/1s,

y Hinter-nays.

United States Patent O 3,049,422 MICRMETER APPARATUS .lohn M. Lewis,Fort Vlifayiire, Ind., assigner to J. C. Thompson Tool ik Die, Inc.,Fort Wayne, Ind. Fil'ul June 2, 1958, Ser. No; 739,285 26 Claims. (Cl.29-240) The present invention relates to micrometer apparatus andmethod, and more particularly to an apparatus for adjusting or settingvalves and hydraulic valve lifters in reciprocating type internalcompustion engines.

Reciprocating internal combustion engines utilize valves for controllingthe introduction of fuel to and exhaustion of burnt fuel from thecylinders, these valves being controlled in opening and closing bytappets, push-rods or the like which are operatively engageable withrotary timing carns on a cam shaft. In one design of engine, a rockerarm is interposed between the tappet (or pushrod) and the stem of thevalve, this rocker arm being pivotally mounted on a fixed support androcked in response to operative engagement of the tappet with the timingcam. This rocking motion of the rocker arm causes alternative openingand closing of the intakek and exhaust valves.

It is essential in securing proper operation of the engine that thepush-rods and tappets be adjusted with respect to the respective timingcams so as to cause the intake and exhaust valves to open and close atthe proper points in the combustion cycle, and to this end, some type ofadjustment is usually provided for adjustment.

Modern-day engines utilize hydraulic valve lifters in combination withpush-rods for securing improved operation of the engine; however, it isessential that the lifter be adjusted to its mid-travel position inorder to realize the available optimum performance. The rocker arms usedin conjunction ywith the hydraulic valve lifters are pivotally mountedon fixed studs extending from the engine block, nuts being received onthese studs and adjustable to force the rocker arms into operativevengagement with the respective push-rods and the push-rods in turnagainst the piston in the hydraulic valve lifter. By adjusting the studnuts to the proper position, the piston in the hydraulic valve lifter ismoved to its mid-travel position in its cylinder. The only method knownto applicant for adjusting these valve lifters is the one wherein thestud nuts are turned downwardly a sufficient distance to bottom thepiston in its cylinder' to obtain a starting pointV from which anadjustment may be made. This is necessary because of the cumulativemanufacturing tolerances in the mechanism parts. The stud nuts are thenadjusted rearwardly, or, in other words, unscrewed, a fraction of arevolution, the pitch of the threads in the stud nuts being relied uponto provide theadjustment needed to move the valve lifter piston to itsmid-travel position. This methed of adjustment is, of course, subject toerror inasmuch as the threads von the stud nuts are not precisionformed. Also, this stud nut adjustment is eifected manually by aworkman, who relies upon his 'judgment as'to how far the nut is turned.rlhus, adjustment of the valve lifter is not accurately achieved,resulting in avsacrifice of engine performance.

This manual method of adjustment is further subject to the criticismthat in the original manufacture of the engine, it is slow and tediousand therefore consumes con.

It is another object of this invention to provide` an apparatus foradjusting a valve assembly which is automatically operable and achievesthe adjustment with micrometer precision. l j

tit is still another object of this invention to provide a micrometerapparatus automatically operable to provide a precision measurement froma reference point in space, which is automatically located, to a secondpoint spaced therefrom. y

Other objects will become apparent as the description proceeds.

To the accomplishment of the above and related objects, my invention maybe embodiedlin the forms illusrated in the accompanying drawings,attention being called to the fact, however, that the drawings areillustrative only and that specific change maybe made in the speciiicconstructions illustrated and described, so long as the scope of theappended claims -is not violated.

In the drawings: p

FIG. 1 is a side elevation of one embodiment of this invention, in partsection, showing a valve assembly of an internal combustion engineimmediately following an adjustment;

FIG. 2 is a fragmentary sectional view taken substantially along thesection line 2 2 of FIG. l;

FIG. 3 is a schematic diagram of the electrical pneumatic and hydraulicsystem used in conjunction with the apparatus of FG. l;

FIG. 4 is a fragmentary, diagrammatic illustration in part section`showing a second embodiment of this invention; and i FIG. 5 is alongitudinal sectional view of still another embodiment of theinvention.

Y Referring to the drawings, and more particularly to FlG. l, aconventional valve assembly of a typical overhead valve, internalcombustion engine is shown as comprising the usual timing cam 10 mountedfor rotation on a cam shaft 12. In operative engagement with the timingcam 10 is a conventional hydraulic valve'lifter v14 which comprises apiston 16 reciprocablevv Iin a cylinder 18 and a compression spring 20interposed between the piston and the cylinder. A push-rod or tappet 22is engaged at its lower end with the head of the piston 16 and at itsupper end with one arm 24 of the usual rocker arm 26. The rocker arm 26is pivotally or rockably mounted on the motor block 28 by means of astud 30 threaded on its upper end portion 32. The rocker arm 26 isconventionaily a rigid, sheet-metal stamping which is formed with' aclearance hole 33 at the,r base of a conveXed orv dished portion thisVhole '33" receiving the stud 30. In engagement with the inside of theAdished portion is a contour washer or collar 3'4 contoured l conveXly orspherioally to tit the inner surface of the dished portion so that therocker arm is free to swing or pivot in the plane of the drawing. Alocking and adjusting nut 36 is threaded on the stud portion 32 until itengages the collar 34' to secure the rocker arm against removal from thestud 30. n v

The right-hand arm 38' of the rocker armr26 engages the upper end of thevalve stern 40'. Thevalve stem 40 carries the usual valve head 42 whichoperates to open and close the companion port 44 in the cylinder head. Avalve spring 46 normally retains the valve head 42 closed arid functionsin the usual manner. p

In operation and with all parts properly assembled and adjusted,rotation of the timing cam 10 produces reciprocation of the valve lifter14 and its push-rod 22. Thisy action is transmitted to the rockerarmj26, causing it to rock about the mounting `stud 30 and in turn tocausereciprocation of the valve 42. The forces 4of the two springs 2t)and 46 coact to provide a constant upward force on the rocker arm 26which holds the latter into assembly against the contour washer 34.

Conventional hydraulic valve lifters, such as the one just described,must be properly adjusted in order to achieve proper operation thereof.Since the valve lifter is composed of a cylinder `18 and piston 16 andthe piston 16 must be free to reciprocate in opposite directions from amid-travel position, it is obviously necessary that the piston 16 beoriginally adjusted or set in its cylinder 18. This adjustment isachieved, according to one method, by turning the stud nut 36 downwardlyon the mounting stud 30 until the piston 16 is bottomed in the cylinder18. I-n other words, the lower end of the piston 16 -is abutted againstthe :lower end of the cylinder 18. The nut 36 is next turned upwardly,or, in other words, unscrewed, a suiicient distance to permit the spring2t) to move the piston 16 to its mid-travel position. Knowing the pitchof the threads, it may be predetermined that a partial revolution of thenut 36 will position the piston 16 at its mid-travel point in thecylinder. In other words, after tightening the nut 36 to the point atwhich the piston16 is bottomed in its cylinder, a threequarter reverseturn of the nut will set the piston 16 at its mid-travel position,assuming, of course, that the pitch of the threads is such as willprovide this adjustment. Another method is to turn the nut 36 downwardlythreequarters of a turn from the point at which slack in the assembly istaken up, again relying on thread pitch for accuracy.

These methods of adjustment have been used primarily for the reason thatmanufacturing tolerances in the Various parts are cumulative and cannotbe predicted with any fair degree of accuracy prior to the assemblyoperation, unless, o f course, they are precisely measured. Since, inthe mass production of automotive engines, it is of prime concern to theeconomy of manufacturing that precision requirements be kept toa-minimum, it being considerably more time-consuming and expensive tomanufacture a part with a high degree of precision, all the parts usedin the conventional valve-operating mechanisms, in the interests ofeconomy and insofar as possible, 'are manufactured with only a lowdegree of precision.

The present invention provides an apparatus and method which operate ina manner which is the antithesis of the p'rior methods; i.e., in theadjusting operation, the nut 36 is merely turned downwardly in a singleoperation until the piston 16 is properly set toits midtravel position.In achieving this adjustment, i-t is not necessary partially to returnor unscrew the nut 36 in order to secure adjustment, nor is it necessaryto rely onthread pitch for securing a length of adjustment.

The apparatus of this invention comprises a conventional nut or studdriver 48 having a rotary wrench or socket 50 which tits the nut 36.Preferably, this stud driver `48 is powered by an air motor, but, ofcourse, this invention is not limited thereto. Such stud driversconventionally incorpora-te torque-limiting means which automaticallycontrol the rotation of the socket 50 when reactionary torques in excessof a predetermined value are encountered. Suice it to say, the studdriver used in this invention is conventional and is available on theopen market.

The stud driver 48 is securely mounted on a steel or the like frame 52.To the upper end of this framel S2 is secured a piston rod 54 of areciprocable iai-r motor 56, the cylinder of this motor being stationaryand xedly secured to some suitably rigid framing structure (not shown)which is fastened directly to or with respect to the engine 28. By meansof this mounting arrangement, the motor 56 may be operated to produceselective reciprocatory movement of the frame 52 with respect to theengine 28 and all of the parts mounted thereon. A stop s-leeve 57 insidethe cylinder 56 limits protraction of the piston Aand its rod 54 toprevent over-travel of the frame 52.

On one `side of Ithe frame 52 is mounted a reciprocating type air motoror cylinder 58 having a reciprocable plunger 60 extending from the endthereof. A clevis 62 is mounted on the lower end of the plunger 60 andpivotally mounts a clamping arm 64, preferably `bifurcated at its outerend to straddle the wrench or socket 50 and the nut 36. As shown, theouter ends of the furcations 66 are offset downwardly slightly and areengageable with the upper respective portions of the rocker Varm 26.This engagement is assured by a suitably preformed bar spring 68 whichis secured to the plunger 60 to bear against the clamping arm 64. Thearm 64 is therefore yieldably urged counterclockwise about its pivot.

0f importance is -the fact that the force exerted by this bar spring 68as it operatively bear-s against the clamping arm 64 and the rocker arm26 is insufficient to cause any compression of the spring 2t) in thehydraulic valve lifter. The primary purpose of this clamping arm 64 isto force gently the rocker arm 26 downwardly into engagement with theends of the valve stem 40 and pushrod 22 and, in turn, to produce a firmbut gentle engagement of all the valve-operating part-s. This takes upany slack motion in the assembly. Of course, since the valve spring 46is much stronger than the lifter spring 2t), neither of the two springs46 and 20 ywill be compressed by the clamping spring 68 nor will thepiston I16 be moved.

The air cylinder 58 is operable to protract the clamping arm 64 intoengagement with the rocker arm 26 as well as to retract the clamping armfrom engagement therewith.

On the side of the frame 52 opposite the air cylinder 53 is ixedlymounted a hydraulic cylinder 70 which reciprocably receives the usualpiston 72 (see FIG. 2). Secured to and extending from the piston 72 isthe usual piston rod 74, this piston rod carrying on its outer end ahousing or supporting member 76 which is characterized as a sensinghead. This sensing head is preferably formed of aluminum or theequivalent to maintain the inertia at the lowest possible level. Inorder to prevent the sensing head from rotating with the piston 72, areciproca-ble guide or support 78 is secured at one end to the back side(see FIG. 2) of the sensing head 76 and at its other end is providedwith two spaced, longitudinally extending slots 80. These slots receivesuitable pins or Aguide blocks secured to the side of the cylinder 7i),`a slight clearance being provided between these pins 82 and therespective slots Si). By means of this mounting arrangement,reciprocating movement of the piston rod 74 produces the same movementof the sensing head 76, since the supporting guide 78 is capable oflongitudinal, sliding movement with respect to the cylinder 70.

As seen more clearly in FlG. l, the sensing head 76 carries internallythereof a sensing finger S4 which is a common lever pivoted intermediateits ends on a pin S6 mounted transversely in and movable with thesensing head 76. A compression spring 88, fitted in a suitable socket inthe sensing head 76, extends into engagement with the lower arm of thesensing finger, tending to pivot the latter in a clockwise direction. 92of the sensing finger normally engages and holds open an electrical ormicro-switch 94. This micro-switch is of the single pole, single throwVariety, and is normally spring-biased to a closed position. However, byreason of the engagement of the arm 92 therewith, the switch is heldopen.

This switch 94 is mounted for adjustment inside the sensing head 76,this mounting being provided by means of a suitable bracket 96 which isslidably received in a milled groove 98 in the back wall of the sensinghead 76. A precision micrometer 100 having a shaft extending through theend of the wall 102 of the sensing head 76 is connected to the bracket96 such that adjustment The upper armof the micrometer 1th) will effectreciprocatory movement of the bracket 96 in its trackway or groove 9%.The micro-switch 94 is secured to the bracket 96 and' will, of course,move therewith. By this means of adjusting the switch 94, it is possibleto alter the point inside of the sensing head 76 at which the arm 92will engage the switch. A second single pole, double throw switch 164 ismounted directly on the rear wall of the sensing head 76 on the side ofthe arm 92 opposite the switch 94. This switch 104 is spaced from thearm 92 when the latter is engaged with the switch 94, and is sopositioned that counterclockwise movement of the finger S4 about itspivot will cause engagement of the arm 92 with the switch 104; The twoswitches 94 and 104 are spaced sufficiently far apart that in movingthearm 92 first out of engagement with the switch 94 and secondly intoengagement with the otherswitch 194, the switch 94 will be disengaged oractuated prior to engagement or actuation of switch 1114. The samesequence of disengagement and engagement in reverse order follows whenthe arm 92 moves from the switch 194 to the switch 94. The spacing ofthese two switches determines the length of measurement by theapparatus.

As seen in FIG. l, the lower arm y90A of the sensing finger ishook-shaped with the end engaging the upper surface of the rocker arm 26at a point 106 adjacent the upper extremity of the push-rod 22. Thereason for this engagement will be explained further in the following.

Considering for the moment only the operation of the sensing head 76,its primary function is to locate a position in space, eg., the point106 at which the arm 9i! engages the rocker arm 26. This locatingfunction is accomplished in the following manner. The hydraulic cylinder70 is operable to protract the sensing head 76 in the direction of thearrow F, as shown in FIG. 2. Hydraulic fluid under pressure introducedinto the cylinder chamber 198 bears against the piston '72,' resultingin movementl of the sensing head '76. The return spring 110 bearingagainst the opposite side of piston 72 rc- Vtracts the piston and thesensing head 76when the hydraulic pressure in the chamber' 1618 isrelieved.

In starting operation, the piston 72 is fully retracted and no hydraulicpressure is present in the chamber 19?. The sensing head 76 is therebypositioned rearwardly a distance sufficient to space the sensing arm 99'from the rocker arm 26. In this position, the arm 92 engages switch 94.Upon introduction of liquid under pressure to the chamber 168, thesensing head 76 is moved forwardly until the sensing arm 90 engages therocker arm 26 at point 106. Continued protractile movement of thesensing head now results in swinging the sensing finger 34 about itspivot 86 until such time as engagement with the -switch 94 is broken andengagement with the switch 104 is made. Suitable electrical andhydraulic circuitry properly coupled to the two switches 94 and 194 aswell as to the hydraulic cylinder 70" results in immediate stopping andlocking of the piston 72 as well as the sensing head 76 in position. Inthis position, the sensing arm 90 is engaged with point 106 on therocker arm and the arm 92 in operative engagement with the switch 194.As already stated, `and this is important with respect to the properoperation of the invention, the sensing head '76 is locked in position.The means for locking the sensing head will be explained later on.

The point 106 may now be said to be established or located in space, andinsofar as the further operation is concerned, the mechanism will eectan accurate measurement axially downwardly of the push-rod 22 from thispoint 106. By threading the stud nut 36 downwardly, as explainedyearlier, the rocker arm 26 will also be moved downwardly. This movementis in a direction away from the sensing arm 90, 4and the sensing head 76being locked, the arm 90 will swing clockwise about its pivot $6,causing the arm 92 to leave the switch 104 and engage the switch 94. Themoment the switch 94 is engaged, the electrical and hydraulic circuitry,to be described hereinafter, stops the stud driver 48, thereuponstopping the threading action of the nut 36. The operation of adjustmentis now complete, the lifter piston 16 having been depressed to itsmid-travel position, and the hydraulic cylinder 70 is deactuated,permitting the sensing head 76 to retract under the force of the returnspring 1!10.

In FIG. 3 is illustrated, in schematic form, the electrical pneumaticand hydraulic system which is used to effect the .operation of theapparatus thus far described. The hydraulic system comprises a variablevolume cylinder 112 having a reciprocable piston 114 which defines twovariable volume chambers 116 and 118, respectively, on opposite sidesthereof. The chamber 118 is connected by a hydraulic line 120 to thechamber 108 of the cylinder 70, a normally open hydraulic valve 122being seriesconnected in the line 1'20. This valve 1:22 is equipped withthe usual electrical solenoid or electromagnetic actuator which isselectively operable to open and close the valve.

The chamber 118, line 120' and the chamber 108 of this hydraulic systemare filled completely with hydraulic fluid, with all air or compressiblefluids being exhausted or bled therefrom. Thus, movement of the piston114' toward the right resultsy in corresponding movementvof the sensingpiston72. By closing the Valve 122, the hydraulic fluid is locked in thechamber 198, thereby preventing the piston 7 2 from moving. Rearwardmovement is prevented, because the hydraulic fluid is non-compressible.Forward movement is prevented by reason of the spring 1111 and air oratmospheric pressure bearing on the right-hand face of the piston 72.

The chamber 1.16 of the cylinder 112 is pneumatic, meaning that it isadapte-d to receive -air under pressure for effecting movement of thepistony114. An air line y124 is connected to this chamber 116, anormally closed air valve 126 being connected in series with this line.This m'r valve 126 is electrically operated, being equipped with asolenoid or suitable electromagnetic actuator which is selectivelyoperable to open the valve upon the receipt of an energizing voltage.The clamping cylinder 58 is pneumatically operated and is connected tothe line 124 through a one-way ball check valve 125 or the equivalent.The return spring 1284 bearing against .the clamping piston exerts `aretracting force thereon and otherwise prevents protractile movement ofthe piston unless air under pressure is applied thereto. A manuallyoperable exhaust valve 127 connects to the cylinder 58 for controllingthe release of pneumatic pressure in the cylinder.

Of importance is the fact that the clamping cylinder 58 is designed tobe faster acting than any other of the apparatus components. By this ismeant, now referring to FIG. l, when the apparatus is' first actuated,the clamp ing cylinder 58 operates first to move the clamping lever 64into engagement with the rocker arm 26. Thereafter, the sensing head 76is protracted to eiiect engagement of the sensing finger with the rockerarm. While this sequential operation is `achieved preferably by simplyselecting a clamping cylinder 58 which is faster acting than the otherapparatus components, the use of restrictions or valves in the pneumaticand hydraulic lines of the system at desired locations will effect thesame end result. For example, a restriction could be inserted betweenthe chamber 116 `and the line 124 which will prevent the piston 114 frommoving' as rapidly as the clamping piston 130. v

' By opening the valve 126, air under pressure admitted to the line 124will result in protraction of the piston 114. This results indisplacement of the hydraulic uid in the chamber 112 which flows throughthe valve 122 and line 12h into the chamber 10-8. This displaced fluidthen protracts the piston 72. Relieving this air pressure admitted tothe Iline 124 or exhausting the pressure through the valve 126 permitsYthe return spring 110` in the\cylinder 76 to force the piston 72rearwardly, thereby displacing the liquid rearwardly into the chamber118. A second air line 132 is coupled to the stud driver 48 through anormally closed air valve 134 whichmay be of the same design as that ofvalve 126. Air pressure admitted to this line 132 and fed to the studdriver 48 eectuates forceful rotation of the wrench or socket 50.

The electrical circuitry of the system will now be described. Twoelectromagnetic control relays, indicated generally by the referencenumerals 136 and 138, are provided with the usual actuating coils 140and 142, respectively. The relay 136 is provided with two normally openswitches 144 and 146, respectively, while the relay 133 is provided withthree normally open switches 148, 150 and 152, respectively. The coil140 is connected across the power line terminals 154 and 1'56 through anormally open starting switch 158. The normally open switch 144 islseries-connected between the upper end of the coil 140 and the statorconta-ct 160 of the switch 104. The switch 146 is-connected in serieswith the electrical actuator of the valve 126 and the lines extendingfrom the power terminals 154 and 156.

The coil 142 of the relay 138 is connected in series with the terminal154 and the stator contact 162 of switch 104. The normally open switch14S is also connected in series with this stator contact 162 and inaddition to the normally open contact 164 of the switch 94.

The normally open switch 150 is connected in series with the electricalactuator of the valve 122 and the power line terminals 154 and 15,6.The'normally open switch 152 is connected in series with electricalactuator of the valve 134 and the two terminals 154 and 156. Thearmature contacts 166 and 168 of the two switches 94 and 104,respectively, are connected together and to the terminal 156. Asmentioned earlier, the movable arm or armature of the switch 94 isspring-biased to engage normally the stator contact 164, and the movablearm of the switch 104 is spring-biased normally to engage the statorcontact 160. The spring 88 in the sensing head normally urges thesensing linger intoy engagement with the switch 94 so as to hold thearmature out of engagement with the fixed contact 164.

The operation of the electrical system may now be explained. Closure ofthe switch 158 results in energizing the coil 140 and closure of the twoswitches 144 and 146. The switch 144 establishes `a hold-in circuit forthe coil 140 via the switch 104. Closure of the switch 146 results inactuation of the air valve 126, opening it and permitting air underpressure to be admitted to the cylinder chamber 116 and to cylinder '58through valve 125. The valve 125 is spring-biased to closed position 0and automatically opens only when air pressure is applied thereto fromline 124. The valve 125 prevents reverse flow `from the cylinder 58. Theclamping cylinder S is iirst to operate fully, movement of the piston114 in the cylinder 112 following displacing the liquid in the chamber118 to the sensing cylinder chamber 108. This results in protraction ofthe sensing head 76 until the sensing inger 90 engages the xed orstationary point 106', at which time the finger 90 is pivoted clockwise,resulting in closure of the switch 94 Iand shifting of the armature inswitch 104 from the contact 160 to the other contact 162. The momentswitch 104 is thus actuated, `an energizing circuit is established tothe `relay coil 142 and the relay coil 140 is de-energized, opening thetwo switches 144 and 146. The cylinder 58 remains actuated, however. Theswitches 148, 150 and 152 close, the switch 148 providing a holdincircuit for the coil 142 via the switch 94. Closure of the switch 150results in actuation and closure of the hydraulic valve 122, thereuponlocking the hydraulic fluid in the chamber S. This prevents the sensingpiston 72 from moving either forwardly or rear- Wardly and, of course,stops movement of the sensing head 76. In this position of the sensinghead, the linger 90 is in engagement with the fixed or reference point106.

Closure of the switch 152 results in establishing a circuit to the valve134, opening it and admitting air under pressure to the stud driver 48.The socket or Wrench 50 is now `caused to rotate, as explained earlier.

Now referring brieliy to FIG. l, as the Wrench 50 rotates, the nut 36will lbe turned downwardly on the stud 30. This results in the referencepoint 106 moving in a direction away from the sensing arm 90, thereuponpermitting the sensing arm to swing about its pivot 86 in a directionwhich permits the armature of the switch 104 to finally break engagementwith thecontact 162 Iand make an engagement with the contact 160.Nothing happens when this switch 104 moves from its contact 162 to itsother contact 160, since the switch 94 establishes a hold-in circuit forthe relay 138. Continued pivoting of the sensing arm 90 causes the arm92 next to engage the switch 94 and to break the engagement with thecontact 164. The moment this happens, the entire system is deactuated orotherwise stopped, the relay 138 being de-energized, thereupon openingthe hydraulic valve 122 and closing the air valve 134. The adjustment ofthe stud nut 36 is now complete, Iand it has been moved downwardly onits stud 30 a distance corresponding to the distance which the sensingringer 92 travels in breaking its engagement with the switch 104 andlinally opening the switch 94. Thus, the distance which the nut 36 maybe threaded on the stud 30, or, in other words, the distance which thenut 30 may be moved downwardly toward the engine block 28, is gauged andcorresponds to the spacing between the two switches 94 and 104. In orderto release the clamping cylinder 58, the valve 127 is operated toexhaust the 'air pressure from the cylinder.

The following will be `an explanation of the operation of the inventionin connection with adjusting the hydraulic valve lifter of FlG. 1.

Ignoring for the moment the adjusting apparatus and considering only thevalve-operating mechanism which comprises the valve lifter 14, thepush-rod 223, the rocker arm 26, the mounting stud 30, and the valvestem 40, the valve lifter 14 and the valve assembly 40, 42, 46 are firstinstalled in the engine. In this installation, the push-rod 22 is firstengaged with the piston 16 of the valve lifter and positionedsubstantially as shown in the drawing. Next, the rocker arm 26 is passedover the stud 30 until it engages and rests on the upper ends of thepush-rod 22 and the valve stem 40. The rocker arm will assumesubstantially the position as shown in the drawing. The contour washers34 is assembled and the nut 36 is started on its threads. This is allthat is required prior to the use of this invention.

During this assembly of the valve-operating parts, the apparatus of thisinvention is, of course, retracted or otherwise removed from the workingarea by means of the power cylinder 56 which carries the frame 52".Immediately following this rough assembly work, the cylinder 56 isactuated, causing the frame `52 to move downwardly along a centerlinewhich places the wrench 50 over the nut 36. ln this position, theclamping cylinder 58 as well as the sensing cylinder 70 are fullyretracted, the sensing head 76 being spaced rearwardly yfrom theposition illustrated and the clamping arm 64 `being simi-iarly spacedrearwardly.

The switch 158 of FIG. 3 may now be closed. This results in theactuation of the air `cylinder 58 which moves the clamping arm 64 intoengagement with the rocker arm 26. The force of the clamping arm againstthe rocker arm moves the push-rod into rm engagement with the lifterpiston 16, and the upper end of the valve stem. 40 is assured, taking upall slack motion therebetween.

With the rocker arm 26 so held in position by means of the clamp 64, thesensing head 76 moves forwardly or outwardly from the cylinder 70 untilthe sensing arm 90 touches the rocker arm at the indicated point 106.The spring 8S which bears against the sensing arm 90 being weaker thanthe hydraulic lifter spring 20, the sensing 9 arm 90 will now begin toswing counterclo'ckwise with continued forward movement of the sensinghead 76. This counterclockwise movement will continue until the arm `92.engages `the switch 104, resulting in actuation of the valve 12,2 andlocking of the sensing head 76 in position. Since the micro-switches 184are relatively fragile and expensive, a third arm engageable with a stopon the sensing head may be provided on the sensing finger 84.

At the moment of this locking, the apparatus has effectively determinedthe spatial position of the rocker arm 26, or, in other words, hasestablished the pointltd as a spatial reference from which a measurementmay now be taken with respect to the engine.

As already explained, the moment the switch 104 is actuated, the studdriver 48 is energized, causing rotation of the wrench 58. This threadsthe nut 86 downwardly on the stud 30, causing a `corresponding downwardmovement of the rocker arm 236. Since the valve spring 46 is relativelystrong, only the lifter spring 28 will be compressed. Compression ofthis lifter spring results from downward movement of the push-rod 22with the rocker arm 26 and corresponding movement of the lifter piston16. When the rocker arm 26, or, more precisely, the point 196, has moved`downwardly a distance which permits the sensing inger to move from theswitch 104 to the switch 94, the' lifter piston 16 will have been moveddownwardly la distance corresponding to the spacing be* tween the twoswitches 94 and 184. lWith the actuation of the switch 94 and the valve127, the system is deactuated, stopping the stud driver 44 and causingthe entire apparatus to retract by means of fluid pressure admitted tothe power cylinder 56. "This completes the adjusting operation of :thelifter piston 16, this adjustment being completely independent ofmanufacturing tolerances in the various valve-operating parts, since theapparatus establishes a reference point in space and makes a measurementfrom this reference point. For example, if the push-rod Z2 were aneighth of an inch longer than that shown, the sensing head 76 wouldnevertheless provide a measurement of the same length' or distance.Thus, manufacturing tolerances in the valve-operating parts may beappreciably relaxed, thereby leading to substantial economies 4in theproduction of these parts. IAlso, relaxation or tolerance requirementsreduces appreoiably the number of parts rejections, thereby lowering theoverall cost. is, for all practical purposes, fully automatic, it isable to complete an adjustment inva matter of seconds, 'which normallyrequires an operator or workman considerably more time by the priormethod.

From the foregoing, it will now be apparent that the method of thisinvention comprises the steps of first clamping the rocker arm 26 forthe purpose of. taking up any slack motion in the push-rod 22 and othervalve-` operating parts. Next, the sensing head 76 establishes thespatial position of the Arocker arm 26 from which an adjustment may bemeasured. Thirdly, the rocker arm Z6 is adjusted downwardly until the`lifter piston 16 reaches its mid-travel position, at which point thesensing head 76 completes its measurement from the reference point andstops the operation of the mechanism. This method of adjustment eiiectsan accurate and precise setting of the valve-operating parts. While themethod has been described as being particularly adapted to theadjustment ot hydraulic valve litters, it will of course appear obviousto persons skilled in the art that the same method may be employed inadjusting other mechanisms, for example, the conventional screw-type,valve tappets.

A second embodiment ofthe present invention is shown in FIG. 4. Likenumerals will indicate like parts. The sensing head of this embodimentemploys as a sensing finger a plunger Vor reciprocable member 172 whichprojects ythrough the end wall of the sensing head 76 and isspring-biased outwardly by a compression spring 174. An arm 175 extendslaterally from the plunger 172 and Still further, since the apparatus ofthis invention is movable between and engageable with the two switches94 and 104. The sensing head 76, instead of being operated by means of ahydraulic cylinder, is mounted on a rack 176 engageable by a pinion of areversible electric motor 178. A return spring may be connected betweenthe end ofthe rack 1'76 for exerting arretracting force thereon toinsure complete withdrawal of the sensing head 76 from the rocker armwhen the adjusting cycle has been completed.

The plunger arm 175 normally engages the switch 94, as illustrated bythe dashed outline of the arm, by means of the spring 174. When `themotor 178 is energized to advance the sensing head 76 toward the rockerarm 26, the outer end of theV plunger 172y will engage the rocker armand will -move rearwardly with respect to the sensing head 76 as thelatter continues to advance. Eventually, the arm 175 engages andactuates the switch 104 which is connected to suitable, conventionalcircuitry for de-energizing the motor 178 and for locking or clamping abrake on the motor' to hold the sensing head 76 in position. The studnut 36a having a convex underside is next turned downwardly on the stud30, moving the rocker arm 26 away from the sensing head 76. This permitsthe plunger arm 17S to disengage the switch 184 and engage the switch94. The switch 94, as in the case of FIG. 3, is 4connected intodisabling' circuitry which provides an indication or system operationterminating the adjustment of the nut 36a.

A more refined design and arrangement of the apparatus shown in FIG. 4is found in the third alternative embodiment of this invention, asillustrated in FIG. 5. In this embodiment, the hydraulic sensingcylinder 70a receives a reciprocable piston 72a to which is secured andpassed through a tubular piston rod 74a. Suitable O- ring seals 182 areprovided in the opposite ends of the cylinder 70a to prevent the escapeof pressure liquid. The return spring l10n bears against the piston 72aurging it to its illustrated retracted position. The cylinder 70a isprovided with an end plug 184 centrally bored' to slidably receivetherethrough the extended piston rod 74a. Again, a suitable O-ring seal186'is provided between this plug and the piston rod 74a to prevent theescape of pressure liquid from the cylinder. On the right-hand end ofthe coaxially extended piston rod 74a is received a rst carrier block188. This carrier block may be cylindrical in shape with a flat on oneside, this flat having mounted thereon the micro-switch 94a. This switch94a may be identical to the switch 94 of FIGS. l, 2 and 5. Spaced fromthe first carrier block 188 is a second carrier block which is alsoprovided with a ilat on one side for mounting the second switch 104:1.Suitable pins or mounting means may be used for securing the two carrierblocks 188 and 190 together. Thus, the two carrier blocks 188 and 190are fixedly secured to the piston rod 74a and Will therefore move withthe piston 72a.

A- sensingV rod or pin 194 is telescopically received through the pistonrod 74a and projects outwardly as' shown from the left-hand end of thepiston rod as well as from the right-hand end as shown. The carrierblock 199 is provided with an enlarged -bore which receives theright-hand end of the pin 194 so that the pin is capable of free-slidingmovement relative to the piston rod 74a as well as the two carrierblocks 188` and 19t).

On the sensing pin 194 andv in the space between the two carrier blocks188 and 190 is mounted and secured a sensing cam 196 which is heldnormally in operative engagement with the switch 94a by means of acompression spring 198. This sensingl cam 196 is also operativelyengageable with the switch 104:1 when the sensing pin 194 is movedtoward the iight relative to the piston rod 74a.

In this embodiment of FIG. 5, the piston rod 74a in combinationwith thecarrier blocks 188 and 190 may be functionally compared to the sensinghead 76 of FIG.

1i 1. The cylinder 70a is fixedly mounted on a frame the same as thecylinder 70 of FIG. 1. In operation, hydraulic fluid under pressure isadmitted to the righthand side of the piston 72a which forces the lattertoward the left and carries with it both the piston rod 74a and thesensing pin 194. When the sensing pin 194 engages the work-piece such asthe rocker arm 26, the sensing pin is moved rearwardly with respect tothe piston rod 74a until the switch 94a is de-actuated and the switch104 is actuated. When this happens, the liquid in the cylinder 79a islocked or otherwise prevented from escaping and the Work-piece (rockerarm 26') is moved in a direction away from (toward the left) the end ofthe sensing pin 94. This permits the sensing pin to move leftwardrelative to the piston rod 74a under the force of the spring 198, whicheventually results in deactuation of the switch140a and actuation of theswitch 94a. When this occurs, a positive indication is produced that theadjusting operation has been completed.

Preferably, the carrier block 190 is provided with an adjusting screwfor varying the spacing Abetween the two blocks 188 and 190. By thismeans, the micrometer adjustment made possible by means of the relativemovement between the sensing pin 194 and the piston rod 74a may bepreset to that desired.

`ln some instances, the embodiment of lFIG. S is preferred over that oflFIG. 1. Note, for example, that the sensing ringer 84 of FIG. l isswingable about a pivot 86. Also note that the push-rod 22 movesaxially,or, in other words, linearly. By reason of the arcuate motion of thepoint of contact of the sensing linger 84 with the rocker a-rm 26, therectilinear movement of the push-rod n 22 cannot be linearly related tothe angular movement of the finger 84. In the embodiment of FIG. 5, afull, linear relationship exists, because the sensing pin 194 moves insubstantially the same direction or parallel to the direction ofadjustment of the push-rod 22, whereupon sensing pin movement 194 isdirectly, linearly related to the adjustment of the push-rod 22 over anydistance through which an adjustment might be made. Thus, the micrometerof FIG. is capable of providin-g linear adjustments over a longerdistance than is true of the ernbodiment of FIG. 1. However, theapparatus of FIG. 1 is preferred in those instances in which spacelimitations require that the cylinder 70* be offset from the Workpiece(26), as is true in setting the rocker arm 26.

Therfundamental principles of this invention are capable of beingutilizeddn the provision of micrometer apparatus which performs nofunction other than to measure distances `from a reference point inspace. For example, the apparatus of FIG. 1 -could have eliminatedtherefrom the stud driver 48, and an indicator light or the like could,be substituted in series with the switch 152 of FIG. 3 instead of thevalve 134. Thus, when the micrometer apparatus responded to the manualthreading of the stud nut 36 onto the stud 30, the indicator light wouldash on, indicating that the adjustment is complete. The apparatus thusbecomes a micrometer capable of finding a reference point in space andproviding a precise measurement Ifrom this reference point.

Of particular importance in this invention is lthe provision of ahydraulic cylinder as the device for operating the sensing heads 76 and70a. This hydraulic cylinder (cylinders 70 and 70a) is preferably smallin size, approximately one (l) inch in diameter and four (4) inches inlength. Being of such small size, only a small amount of hydraulic huidis required to displace the piston (7-2, 72a). This small amount offluid obviously possesses only negligible inertia so that over-shootingdue to the momentum of the moving parts is either nonexistent ornegligible. This makes it possible, merely by closing the hydraulicvalve 122 of FIG. 3, to stop immediately and position precisely thesensing head 76. The oil being incompressible, the sensing head cannotbe moved rearwardly after the valve 122 is closed. Also, the sensinghead cannot be moved fo1wardly because of atmospheric pressure bearingagainst the piston. As will now be apparent, this negligible inertia inthe hydraulic system contributes greatly to the preciseness with whichmeasurements may be taken, and since the present invention is directedto the principle of preciseness of measurement, the use of hydraulics inmoving and locking the sensing head in adjusted position becomesimportant.

While the present invention has been explained in connection with theadjustment of hydraulic valve lifters in reciprocating engines, it willof course appear as obvious to a person skilled in the art that theapparatus is useful for adjusting other types of mechanism. 'In anyevent, the present invention is accurately operable irrespective ofmanufacturing tolerances in the parts `being adjusted, this featurelbeing doubly significant in the respect that iirst the adjustingoperation is substantially automatic and, secondly, requires lessaccurately fabricated parts in the assembly 'being adjusted. Many otheradvantages and attributes will appear as obvious to a person skilled inthe art.

What is claimed is:

l. Micrometer apparatus comprising a frame, la hydraulic sensingcylinder mounted on said frame and having a reciprocable piston rod, asensing head tixedly secured to said piston rod for reciprocablemovement therewith, said sensing head comprising a housing, a leverpivotally mounted intermediate its ends in said housing and having oneend projecting therefrom in a direction transverse to the direction ofpiston rod movement, an arm on said lever extending at an angletherefrom, a stop in said housing engageable by said `arm when saidlever is pivoted in one direction, a spring in said housing bearingagainst said lever tending to pivot it in the opposite direction, twoelectrical switches mounted in said housing on oppositesides,rrespectively, of the other end of said lever, said switches beingalternatively engageable and actuaole by said other lever end when saidlever is pivotally moved, said spring normally holding said lever intooperative engagement with one of said switches, a micrometer screwadjustably received through one wall of said housing and carrying saidone switch for adjustment with respect to said lever and the otherswitch; a rigid guide bar secured at one end to said housing and beingoperatively mounted on said frame for reciprocable movement in adirection parallel to the movement ofl said piston rod, the mounting ofsaid bar on said frame comprising at least one slot in said bar whichslidably receives a mounting stud extending from said hydrauliccylinder, a rotary stud driver mounted on said frame along a linesubstantially parallel to the line of movement of said sensing head,said stud driver including aV rotary air motor for driving the same,both said one end of said lever and said stud driver being operativelyengageable with a work-piece, a pneumatic clamping cylinder mounted onsaid frame and having a plunger reciprocable along a line substantiallyparallel to the line of movement of said sensing head; said clamping`cylinder including a clamping arm pivotally mounted on the outer end ofsaid plunger and extending in a direction transverse to the axis of saidplunger, said clamping `arm eing disposed adjacent said one end of saidlever so Vas to be operatively engageable with said work-piece,saidhydraulic and pneumatic cylinders being parallel with the protractilemovements of said piston rod and plunger being in the same directionwhereby said one lever end and said clamping arm operatively engage thesame portion of said work-piece, a bar spring on said plunger engageablewith said clamping arm and preformed to pivot the latter in saidprotractile direction, and a reciprocable device connected to said framefor moving the latter substantially rectilinearly in a directionparallel to said protractile direction.

2. The apparatus of claim l and including means for actuating saidclamping cylinder, said hydraulic cylinder 13 and said stud driver, saidmeans comprising said two electrical switches, said switches being ofthe single pole, double throw type normallyv thrown to `one of the twooperating positions, the movable contacts of said switches beingconnected together and in turn connected to one terminal of a twoterminal power source, tWo electromagnetic control switches, one controlswitch having a coil which is connected at one end to the other terminalof said source and at the other end to said one terminal through amanually controlled switch, said one control switch having two normallyopen switches, one of said normally open switches beingV connected inseries between said other coil end and the normally closed statorcontact of one of said electrical switches, a irst electromagneticpneumatic valve which is normally closed, said pneumatic valve beingconnected in series with the other normally open switch and said twosource terminals, the other of saidV electromagnetic control switcheshaving first, second and third normally open switches and a coil whichis connected at one end to said other terminal and at its opposite endto the normally open stator contact of said one electrical switch, saidnormally open stator contact of said one electrical switch beingconnected in series with said iirst switch of said other control switchand the normally open stator contact of the other electrical switch, anormally open electromagnetic hydraulic valve connected in series withthe second switchl of said other control switch and said two terminals,a second normally closed electromagnetic pneumatic valve connected inseries with said third switch of said other control switch and said twoterminals, a pneumatic pressure line connected in series with saidsecond valve and said stud driver, a pneumatically operated hydrauliccylinder connected in series with and between said iirst pneumatic valveand said hydraulic valve, a pneumatic pressure line series connectingsaid iirst pneumatic valve to said clamping cylinder, a hydraulic lineseries connecting said pneumatically operated hydraulic cylinder andsaid hydraulic valve to said hydraulic sensing cylinder, a return springin said sensing cylinder urging said piston rod in a retractiledirection, said clamping cylinder being faster acting than the otherapparatus components so that said plunger when actuated protracts aheadof said piston rod, whereby said clam-ping arm iirst operatively engagesthe work-piece followed by the operative engagement therewith of saidsensing lever and said stud driver, said two electrical switches beingspaced from said other lever end respective distances which providesequential actuation thereof by said other lever end.

3. Micrometer apparatus comprising a frame, a hydraulic sensing'cylinder mounted on said frame and having a reciprocable piston rod, asensing head xe'dly secured to said piston rod for reciprocable movementtherewith, said sensing head comprising a housing, a lever pivotallymounted intermediate its ends in said housing and having one endprojecting therefrom in a direction transverse to the direction ofpiston rod movement, a spring in said housing bearing against said levertending to pivotV it in one direction, two electrical switches mountedin said housing on opposite sides, respectively, of the other end ofsaid lever, said switches being alternatively engageable and actuable bysaidrother lever end when said lever is pivotally moved, said springnormally holding said other lever end into operative engagement With oneof said switches, a micrometer screw adjustably received through onewall of said housing and carrying one of said switches for adjustmentwith respect to said lever and the other switch; `a rigid guide barsecured at one end to said housing and being operatively mounted on saidframe for reciprocable movement in a direction parallel to the movementof said piston rod, the mounting of said member on said frame comprisingat least one slot in said member which slidably receives `a mountingstud extending from said hydraulic cylinder, a rotary stud drivermounted on said trarne along a line substantially parallel to the lineof movement of said sensing head, said stud driver including an airmotor for driving the same, both said one end of said lever and saidstud driver being operatively engageable with a Work-piece, a pneumaticclamping cylinder mounted on said frame and having a plungerreciprocable along a line substantially parallel to the line ot movementof said sensing head; said clamping cylinder including a clamping armpivotally -mounted on the outer end of said plunger and extending in adirection transverse to the axis of said plunger, said clamping armbeing disposed adjacent said other end of said lever so as to beoperatively engageable with said work-piece, said hydraulic andpneumatic cylinders being parallel with the protractile movements ofsaid piston rod and plunger being in the same direction whereby said onelever end and said clamping arm operatively engage the same portion ofsaid work-piece, and a spring on said plunger engageable with saidclamping arm `and preformed to pivot the latter in said protractiledirection.

4. Micrometer apparatus comprising a frame, a hydraulic sensing cylindermounted'on said frame and having a reciprocable piston rod, a sensinghead iixedly secured to said piston rod for reciprocable movementtherewith, said sensing head comprising a housing, a lever pivotallymounted intermediate its ends in said housing and having one endprojectingV therefrom in a direction transverse to the direction ofpiston rod movement, a spring in said housing bearing against said levertending to pivot it in one direction, two electrical switches mounted insaid housing on opposite sides, respectively, of the other end of saidlever, said switches being alternatively engageable and actuable by saidother lever end when said lever is pivotally moved, said spring normallyholding saidr lever into operative engagement with one of said switches;a rigid guide bar secured at one end to saidr housing and beingoperatively mounted on said framevfor reciprocable movement in adirection parallel to the movement of said piston rod, the mounting ofsaid member on said frame com- -prising at least one slot in said memberwhich slidably receives a mounting stud extending from said hydrauliccylinder, a rotary stud driver mounted on said frame along a linesubstantially parallel to the line of movement of said sensing head,said stud driver including an air motor for driving the same, both saidone end of said lever and said stud driver being operatively engageablewith a common work-piece, a pneumatic clamping cylinder mounted on saidframe and having a plunger reciprocable along a line substantiallyparallel to the line of movement of said sensing head; said clampingcylinder including a clamping arm pivotally mounted on the outer end ofsaid plunger and'extending' in a direction transverse to the axis ofsaid plunger, said clamping arrn being disposed adjacent said other endof' said lever so as to be operatively engageable with said work-piece,said hydraulic and pneumatic cylinders being positioned in parallel withthe protractile movements of said piston rod and plunger being in thesame direction whereby said one lever end and said clamping armoperatively engage the same portion of said workpiece, and a spring onsaid plunger engageable with said clamping arm and preformed `to pivotthe latter in said protra'ctile direction.

5. Micrometer apparatus comprising a frame, a hydraulic sensing cylindermounted on said frame and'having a reciprocable piston rod, a sensinghead lixedly secured to said piston rod for reciprocable movementtherewith, said sensing head comprisingv a housing, a lever pivotallymounted intermediate its ends in said housing and having one endprojecting therefrom in a direction transverse to the direction of saidpiston rod movement, a spring in said housing bearing against said levertending to pivot it in one direction, two electrical'switches mounted insaid housing on opposite sides, respectively, of the other end of saidlever, said switches being alternatively engageable and actuable by saidother lever end when said lever is pivoti "5 ally moved, said springnormally holding' said lever into operative engagement with one of saidswitches; a Irotary stud driver mounted on said frame along a linesubstantially parallel to the line of movement of said sensing head,said'stud driver including an air motor for driving the same, both saidone end of said lever and said stud driver being operatively engageablewith a common work-piece, a pneumatic clamping cylinder mounted on saidframe and having a plunger reciprocable along a line substantiallyparallel to the line of movement of said sensing head;

said clamping cylinder including a clamping arm pivotally mounted on theouter end of said plunger and extending in a direction transverse to theaxis of said plunger, said clamping arm lbeing disposed adjacent saidother end of said lever so as to be operatively engageable with saidwork-piece, said hydraulic and pneumatic cylinders being positioned inparallel with the protractile movements of said piston rod and plungerbeing in the same direction whereby said one lever end and said clampingarm operatively engage the same portion of said work-piece, and a springon said plunger engageable with said clamping arm and preformed to pivotthe latter in said protractile direction.

6. The apparatus of claim and including means for actuating saidclamping cylinder, said hydraulic cylinder and said stud driver, saidmeans comprising said two electrical switches each having a movablecontact, said one switch being a single pole normally closed switchwhich is held open by the engagement therewith of said one lever arm,the other switch being of the single pole, double throw .type normallythrown to one of its two operating positions, the movable contacts ofsaid switches being connected together and in turn connected to oneterminal of a two terminal power source, two electromagnetic controlswitches, one control switch having a coil which is operativelyconnected across said terminals, said one control switch having twonormally open switches, one of said normally open switches beingconnected in series with said coil and the normally closed statorcontact of said other electric switch, a first electromagnetic pneumaticValve which is normally closed, said pneumatic Valve being connected inseries with the other normally open switch and said two sourceterminals, the other of said electromagnetic control switches havingfirst, second and third normally open switches and a coil which isconnected at one end to said other terminal and at its opposite end tothe normally open stator contact of said other electrical switch, saidnormally open stator contact being -connected in series with said firstswitch of said other control switch and said one electrical switch, yanormally open electromagnetic hydraulic valve connected in series withthe second switch of said other control switch and said two terminals, asecond normally closed electromagnetic pneumatic valve connected inseries with said third switch of said other control switch and said twoterminals, a pneumatic pressure line connected in series with saidsecond pneumatic valve and said stud driver, a pneumatically operatedhydraulic cylinder connected in series with and vbetween said rstpneumatic valve and said hydraulic valve, a pneumatic pressure lineseries connecting said first pneumatic valve to said clamping cylinder,a hydraulic line series connecting said pneumatically operated hydrauliccylinder and said hydraulic valve to said hydraulic sensing cylinder, areturn spring in said sensing cylinder urging said piston rod in aretractile direction, said clamping cylinder being faster acting thanthe other apparatus components so that said plunger when actuatedprotracts ahead of said piston rod, whereby said clamping arm firstoperatively engages the work-piece followed by the operative engagementtherewith of said sensing lever and said stud driver, said twoelectrical switches being spaced from said other lever end respectivedistances which pro- Vide sequential actuation thereof by said otherlever end.

7. Micrometer apparatus comprising aY frame, a hydraulic sensingcylinder mounted on said frame and having a reciprocable piston rod, asensing head iiXedly secured to said piston rod for reciprocablemovement there with, said sensing head comprising a support, a leverpivotally mounted intermediate its ends on said support and having oneend projecting in a direction transverse to the direction of movement ofsaid member, two electrical switches mounted on said support on oppositesides, respectively, of the other end of said lever, said switches feing alternatively engageable and actuable 'by said other lever end whensaid lever is pivotally moved, said lever normally operatively engagingone of said switches, a stud driver mounted on said frame, said studdriver including a motor for driving the same, both said one end of saidlever and said stud driver being operatively engageable with awork-piece, a clamping mechanism mounted on said frame and having amember movable in a direction substantially parallel to the line ofmovement of said sensing head, said clamping member being disposedadjacent said other end of said lever so as to be operatively engageablewith said work-piece, and means yieldably urging said member in adirection to engage said work-piece.

8. Micrometer apparatus comprising a frame, a hydraulic sensing cylindermounted on said frame and having a reciprocable member, a sensing headfixedly secured to said member yfor reciprocable movement therewith,said sensing head comprising a support, a lever pivotally mountedintermediate its ends on said member and having one end projecting in adirection transverse to the direction of member movement, two electricalswitches mounted in said housing on opposite sides, respectively, of theother end of said lever, said switches being sequentially engageable andactuable by said other lever end when said lever is pivotally moved,said lever normally operatively engaging one of said switches, a studdriver mounted on said frame, said stud driver including a motor fordriving the same, both said one end of said lever and said stud driverbeing operatively engageable with a common work-piece, and a clampingmechanism mounted on said frame and having a yieldable clamping membermovable in a direction substantially parallel to the line of movement ofsaid sensing head, said clamping member being disposed adjacent saidother end of said lever so as to be operatively engageable with saidwork-piece.

9. Micrometer apparatus comprising a frame, a hydraulic sensing cylinderhaving a piston reciprocable therein, said piston defining a variablevolume chamber in said cylinder, a piston rod secured to said piston andextending -from said cylinder, a return spring in said cylinder urgingsaid piston in a retractile direction which tends to reduce the size ofsaid chamber, a hydraulic pressure line connected to said cylinder andcommunieating with said chamber, a normally open hydraulic valveconnected in series with said hydraulic line for controlling pressureliquid delivered to said chamber and the position of said piston,mechanism for closing and opening said valve; a sensing head which isreciprocable with said piston and comprising a supporting member whichis iixedly secured to said piston rod, a sensing finger havin-g twoarms, said sensing finger being pivotally mounted intermediate said armson said supporting member, two electrical switches on said supportingmember on opposite sides, respectively, of one of said arms, said onearm being sequentially engageable with said switches, means urging saidone arm normally into operative engagement with one of said switches,said arm being movable out of operative engagement with said one switchand into operative engagement with the other switch, means adjustablypositioningvsaid one switch with respect to said one arm, the other armof said lever eX- tending in a direction transverse to the direction ofmovement of said sensing head, said other arm being adapted to engage awork-piece; a clamping mechanism on said frame and having a clampingelement disposed in proxbeing sequentially engageable with saidswitches, means urging said one arm normally into operative engagementwith one of said switches, said arm being movable out of element, firstmeans selectively actuating said `clamping v mechanisms, secondmeansdelivering liquid under pressure. to said hydraulic valve for `advancingsaid piston and. saidrsensing head, third means operative in response toactuation of said other switch by said'one arm for closing said valveand locking the liquid in said sensing cylinder andI for actuating saidstudV driver, and fourth means operative in response to astanti-on ofsaid one switch .by saidone arm for opening saidvalve and `deactuatingsaidstud driver. y

l0, Micrometer apparatuscomprising a frame, a hydraulic sensingVcylinder having a piston reciprocafble therein, saidpistonfdening avariable volume chamber in said cylindena piston rod secured to saidpiston and extending from said cylinder, a return spring in saidcylinder urging said piston in a retractile direction `which tends toreduce the size of said chamber, a hydraulic pressure linefconnegcted tosaid cylinder and communicatingwith said chamber, a normally openhydraulic valve connected' in series with saidihydraulic line forcontrolling pressure liquidv delivered to said chamber and the positionof said'piston; a sensinghead `which is reciprocable withhsaid pistonand comprising asupporting member Ywhich is iixedly secured to saidpiston rod, a sensing fingerhaving two arms, sai-d sensing finger beingpivotally Y mounted intermediate said arms on said supporting member,two electrical switcheson said supporting member o n opposite sides,respectively, of one of said arms, said one armbeing sequentiallyengageablewith said switches, means urgingl said one arm normally intooperative engagement with one of said switches,V said arm being mova'bleout of operative engagement with said'. one switch Vand into operativeengagement with the other switch, the

otherl arm or" said lever exten'dinggin a direction trans-` verse to'the direction of movement of said sensing head, said other arm beingadapted to` engage a work-piece;

a` clamping mechanism on said frame and having ac lamping element4disposed in proximity to'said other arm, said clamping element beingadapted operatively .to engage said lwork-piece, means `operative tomove said clamping element substantially parallel to the direction 'ofmovement of said sensing head; a` stud driver on said frame and having adriving tool disposedin proximity to saidl sensing linger andV saidclamping element, 'first means selectively actuating said clampingmechanism, second means delivering liquid under pressure' to saidhydraulic operative engagement with said one switch and into operativeengagement with the other switch, the other arm ot'said lever extendingin a direction transverse to the direction of movement of said sensinghead, said other arm being adapted to engage a work-piece; a clampingmechanism on said frame and having a clamping element disposed inproximity to said other arm, said clamping element adapted operativelyto engage said work-piece, means operative to move said clamping elementin the direction of movement of said sensing head; a stud driver on saidframe and having a driving tool disposed in proximity to said= sensingiin-ger and said clamping element, rst means selectively actuating saidclamping mechanism, second means delivering liquid under pressure tosaid hydraulic valve for advancing said piston and said sensing head,Vand third means operative in response to actuation of said other switchby said one arm for` closing said val-ve andtlocking the liquid in saidsensing 'cylinder and for `actuating said `stud driver. t

l2. Micrometer apparatus comprising a frame, a hydraulic sensingcylinderhaving a piston reciprocable therein, said piston defining a variablevolume chamber in said cylinder, la piston rod secured to said pistonand extending from said cylinder, a hydraulic pressure line connected tosaid cylinder and communicating with ysaid y chamber, a normally openhydraulic valve connected in series with said hydraulic line forcontrolling pressure liquid delivered to said chamber and the positionof said piston; ya sensing head which is reciprocable with said y pistonand'comprising a supporting member which is valverfor advancing ,saidpiston and said sensing head,

third means operative in response to actuation of said other switch bysaid one arm for closing said valve and locking the liquid in saidsensing cylinder and for actul ating sai-d studdriver, and fourth meansoperative inA respense to actuation of said one switchby said one armforopening said valve and deactuatingv said stud driver.

lfl-{Micrometery apparatus comprising a frame, a hydraulic VsensingVvcylinder having a piston reciprocable therein, said piston defining avariable volume chamber in said cylinder, 'a piston rod secured to said.piston and extending Afrom ysaid cylinder, la, hydraulic pressure. lineconnected to said cylinder and communicatingwith said chamber, anormally openhydraulic valve, connected in series with said; hydraulic`line for controlling pressure liquid deliyeredv to said chamber andthe4 positionl ofy said piston; a sensing head which is reciprocablewith said piston Iand comprising a supporting member which is iXedlysecured to said piston rod, a sensing dinger having two arms, saidsensing finger being piyotally mounted intermediate said arms on saidsupporting member, two electrical switches on said supporting'member on`opposite sides, respectively, of one of said arms, said one arm iixedlysecured to said piston rod, a sensingiinger pivotalf' ly mounted on-said supporting member, two electrical switches on said-supportingmember on opposite sides, respectively, of said finger, said fingerbeing sequentially engageable with said switches, means urging saidiinger normally into operative engagement with one `of said switches,said finger being movable out of operative engagement with said oneswitch and into operative engagement withthe other switch, said fingerextending in a direction transverse to the direction of movement Kofsaid sensing head and being adapted to engage a work-piece; a clampingmechanism on said frame and having a clamping element disposed inproximity to said finger, said clamping element being adaptedoperatively to engage said work-piece, means operative to mo've saidclamping element substantially parallel to the direction of movement ofsaid sensing head; la stud driver on said frame and having a drivingtool disposed in proximity to said sensing linger and said clampingelement, first means selectively actuating said clamping mechanism,second means-delivering liquid under pressure to saidV hydraulic yvalvefor advancing saidpiston and said sensing head, .and third meansoperative in response to actuation of said other switch by said one forclosing said valve and locking the liquid in said sensingcylinder andfor actuating said stud driver. t

13. Micrometer apparatus? comprising la frame, a hydraulic sensingcylinder having a piston reciprocable therein, said piston defining avariable volume chamber in said cylinder, a pistonrod secured to saidpiston and extending from said cylinder, ai hydraulic pressure lineconnected to said cylinder and communicating with said chamber, anormally open hydraulic valve connected in series with said hydraulicline for controllingpressure liquid delivered to said chamber and theposition of said piston; a sensin-g head which is reciprocable with saidpiston and comprising asupportingmember which is tixedly secured to saidpiston rod, a sensing `finger movably mounted on said supporting member,two electrical switches on said supporting member on opposite sidesrespectively of said linger, said iinger being sequentially engageablewith said switches, means urging said inger yother switch by said fingerfor closing normally into operative engagement with one of saidswitches, said finger being movable out of operative engagement withsaid one switch and into operative engagement with the other switch,said finger being adapted to engage a work-piece; a clamping mechanismon said frame and having a clamping element disposed in proximity tosaid finger, said clamping element being adapted operatively to engagesaid work-piece, -means operative to move said clamping elementsubstantially parallel to the direction of movement of seid sensinghead; a stud driver on said frame and having a driving tool disposed inproximity to said sensing finger and said clamping element, first meansselectively actuating said clamping mechanism, second means deliveringliquid under pressure to said hydraulic valve for advancing said piston`and said sensing head, and third means operative in response toactuation of said other switch by said finger for closing said valve andlocking the liquid in said sensing cylinder and for actuating said studdriver.

14. Micrometer apparatus comprising a frame, a hydraulic sensingcylinder having a piston reciprocable therein, said piston defining avariable volume chamber in said cylinder, a piston rod secured to saidpiston and extending from said cylinder, a hydraulic pressure lineconnected to said cylinder and communicating `with said chamber, anorm-ally open hydraulic valve connected in series with said hydraulicline for controlling pressure liquid delivered to said chamber and theposition of said piston; a sensing head which is reciprocable with saidpiston yand comprising a supporting member which is fixedly secured tosaid piston rod, a sensing finger movably mounted on said supportingmember, two electrical switches on said supporting member on oppositesides respectively of said finger, said finger being sequentiallyengageable wit-h said switches, means urging said finger normally intooperative engagement with one of said switches, said finger beingmovable out of operative engagement with said one switch and intooperative engagement with `the other switch, said finger being adaptedto engage a work-piece; a clamping mechanism on said frame iand having aclamping element disposed in proximity to said finger, said clampingelement being adapted operatively to engage said work-piece, meansoperative to move said clamping element substantially parallel to thedirection of movement of said sensingV head; first means selectivelyyactuating said clamping mechanism, second means delivering liquid underpressure to said hydraulic valve for advancing said piston and saidsensing head, and third means operative in response to actuation of saidsaid valve and locking the liquid in said sensing cylinder.

15. Micrometer apparatus comprising a frame, a hydraulic sensingcylinder having a piston reciprocable therein, said piston defining avariable volume chamber in said cylinder, a piston rod secured to saidpiston and extending from said cylinder, a hydraulic pressurelineconnected to said cylinder and communicating with said chamber, anormally open hydraulic valve connected in series with said hydraulicline for controlling pressure liquid delivered to said chamber and theposition of said piston; ya sensing head which is reciprocable with saidpiston and comprising a supporting member which is fixedly secured tosaid piston rod, a sensing finger movably mounted on said supportingmember, two actuating devices on said supporting member on oppositesidesrespectively of said linger, said finger being sequentiallyengageable with said actuating devices, means urging said fingernormally into operative engagement with one of said actuating devices,said finger being movable out of operative engagement with said oneactuating device and into operative engagement with the other actuatingdevice, said nger being adapted to engage a work-piece; a clampingmechanism on said frame and having a clamping element disposed inproximity to said finger, said clamping element being adapted tooperatively enactuating device by said finger for closing said valve andlocking the liquid in said sensing cylinder.

16. In micrometer apparatus, a hydraulic cylinder which receives apiston for reciprocation, a tubular piston rod secured to said pistonand coaxially extending through the cylinder ends, a return springinside said cylinder which bears against one side of said piston andurges said piston in a retractile direction, Vtwo carrier blocks on oneend of said piston rod, said blocks beingv axially spaced apart withrespect `to said rod, two switches mounted on said blocks respectively,a sensing pin slidably received by and projecting from the opposite endsof said piston rod, a sensing cam fixed to said sensing pin andpositioned in the space between said blocks, said cam beingalternatively operatively engageable with said switches respectively, aspring bearing against said cam for urging it-into engagement with oneof said switches, a hydraulic line connected to said cylinder forsupplying pressure liquid thereto and against the other side of saidpiston for moving the latter in a protractile direction, and a hydraulicvalve in said line for controlling the opening and closing thereof.

17. In micrometer apparatus, a hydraulic cylinder which receives apiston for reciprocation, a tubular'piston rod secured to said pistonand coaxially extending through the cylinder ends, t'wo carrier blockson one end of said piston rod, said blocks being axially spaced apartwith respect to said rod, two switches mounted on said blocksrespectively, a sensing pin slidably received by and projecting from theopposite ends of said piston rod, a sensing cam fixed to said sensingpin and positioned in the space between said blocks, said cam beingalternatively operatively engageable with said switches respectively, aspring bearing against said cam for urging it into engagement with oneof said switches, a 4hydraulic line connected to said cylinder forsupplying pressure liquid thereto and against the side of said pistonfor moving the latter in a protractile direction, and a hydraulic valvein said line for controlling the opening and closing thereof.

18. In micrometer apparatus, a motor, a sensing head mounted forreciprocation and operatively connected to said motor, a sensing plungermounted on said sensing head for reciprocable movement relative thereto,two spaced apart switches mounted on said sensing head, an arm on saidplunger which extends into the space between said switches, said armbeing alternatively and operatively engageable with said switches,spring means urging said arm into engagement with one of said switches,and means connected between said switches and said motor for controllingthe operation of the latter.

19. Micrometer apparatus comprising supporting means, a sensing elementmovably mounted on said supporting means, a positioning mechanismmounted on said supporting means connected to said sensing element andoperative to move the same from a first position-to a second position inengagement with a work piece thereby establishing a reference locationin space, rst means carried by said mechanism and actuatedby saidsensing element responsive to movement of the same` to said secondposition thereof for locking said mechanism against further movement,second means carried by said mechanism and actuated by said sensingelement responsive to movement of the same to said first positionthereof vfor unlocking said mechanism, third means for `yieldably urgingsaid element ltowards said second posiiiiV including means coupled to.said mechanism for moving said member in the same direction as saidelement moves when approaching said second position, and a poweroperated tool mounted on said supporting means and having a tool partengaging said work piece adjacent said element and member, said toolhaving drive means coupled to said first means and actuated therebyresponsive to actuation of said first means.

20. Micrometer apparatus comprising supporting means, a work piece onsaid supporting means and having limited movement with respect theretoin one direction, a clamping device on said supporting meansfmovable toengage said work piece for moving the same tothe limit of movement'insaid one direction, a sensing element movably mounted on said supportingmeans and operatively engageable with said work piece, a positioningmechanism mounted on said supporting means and carrying said sensingelementJ said mechanism being operative to move said sensingelementtoward and away from said work piece, means mounting said sensingelement on said mechanism for alternative movement relative to saidmechanism in said one direction and in an 4opposite `directionresponsive to engagement with said work piece, iirst means carried bysaid mechanism and actuated by said sensing element responsive tomovement of the same in said opposite direction for locking saidmechanism against further movement, second means carried by saidmechanism and actuated by saidy sensing element responsive to movementof the same in said one direction for' unlocking said mechanism, and apower driven tool mounted on said supporting means and adapted to dowork on said work piece, said tool having an operative connection withsaid first means and being actuated thereby in response toV actuation ofsaid first means by said sensing element.

2.1.4 Micrometer apparatus comprising supporting means, a work piece onsaid supporting means and hav-V ing limited movement with respectthereto in one direction, a clamping device on said supporting meansmovp able to engage said Work piece for moving the same to the limit ofymovement in said one direction,'a sensing. element movably mounted onsaid supporting means and vvoperatively engageable lwith said Vworkpiece, a positioning mechanism mounted on said supporting means andcarrying said sensing element, said mechanism being operative to movesaid sensing element toward "and away from said work piece, meansmounting said sensing element on said mechanism for alternativevmovement relative to said mechanism in said one direction and in anopposite direction responsive to engagement with said work piece, firstmeans carried by said mechanism and actuated by said sensing elementresponsive to movement of the same in said opposite direction forlocking said mechanism against 'further movement, and second meanscarried by said mechanism and actuated by said sensing elementresponsive to movement of the same in said one direction for unlockingsaid mechanism.

22. Micrometer apparatus comprising supporting 'means, a work piece onsaid supporting means, a sensing element movably mounted on saidsupporting means and operatively engageable with said work piece, -apositionp* ing mechanism on said supporting means and carrying saidsensing element, said mechanism being operative to move said sensingelement toward andawayvfrom said woik piece, means mounting said sensingelement on said mechanism for alternative movement relative to saidmechanism in one direction and in an opposite vdirection responsive toengagement of said element with said work piece, `first means carried bysaid mechanism and actuated by said sensing element responsive .tomovement of the same in said opposite direction -for locking saidmechanism against further movement, and second means carried by saidmechanism and actuated by said sensing element responsive to movement ofthe same in said one direction for unlocking said mechanism.

23. M-icronleter-v apparatus comprising: supporting means; power meanson said supporting means and having a reciprocal element;V a sensinghead comprising a supporting member secured' to said reciprocal elementand .reciprocal therewith, a sensing element movably mounted on saidsupporting member, two actuating devices on said supporting member, andmeans normally urging said sensingV element into a first position inoperative engagement with one. of said actuating devices, said sensingelement having a portionl adapted to engage a work piece, said sensingelement being movable from said first position into a second position inoperative engagement withfthe other of said actuatingy devicesrre-,sponsive toen agement with .said work iece; la clam in mechanism onsaid supporting means comprising a clamping element adapted operativelyto engage said work piece adjacent said sensing element, and meansoperative to move said clamping element substantially parallel to thedirection of movement of said sensing head; means for actuating said`clamping mechanism thereby to move said clamping element intoengagement with said work piece; means for actuating said power meansthereby to move said sensing element into engagement with said vworkpieceymeans coupling said second actuating device and said powermeans for locking said reciprocal element against further movementresponsive to actuation of said second actuating device; and said powermeans for unlocking said reciprocal elementvresponsive to actuation ofsaid first actuating device.

24. The combination of claim '23 further comprising a power tool on saidsupporting means comprising a tool element engaging said Work pieceadjacent said sensing element and vclamping element, and drive means forsaid tool element coupled to said other actuating device and actuatedresponsive to actuation of said other actuating device.

25. Micrometer apparatus comprising: supporting means; a 'hydrauliccylinder on said supporting means and having a piston reciprocallydisposed therein, a tubular piston rod secured to' said piston andcoaxially extending through thecylinder ends, a return spring insidesaid cylinder which bears against one side of said piston and urges samein a retractile direction, two carrier blocks on one end of said pistonrod, said blocks being axially spaced apart with respect to said rod,two switches mounted on said blocks, respectively, a sensing pinslidably received within said piston rod and having portionsrespectively projecting from the opposite ends of said piston rod, asensing cam secured to one of said sensing pin portions and positionedin the space between said blocks, ra spring bearing against. said camfor urging the same and said sensing pin into a first position with saidcam in engage-ment with one of said switches, the other portion of saidsensing I'pin being adapted to engage a Work piece, said sensing pinbeing movable from said first position into a second position with saidcam in engagement with the other of said switches responsive toengagement of said sensing pin with said work piece; a hydraulic lineconnected to said cylinder for supplying pressune liquid thereto againstthe other side of said piston for moving the same in a'protractiledirection thereby to move said other sensing pin portion into saidsecond position, and a hydraulic valve in said line for selectivelycontrolling the opening `and closing thereof,v said valve being coupledto the other of said switches'and actuated ythereby to close said valvethereby to lock said piston against further protractilemovementyresponsive to actuation of said other of said switches, saidvalve being further coupled to said one of said switches and actuatedthereby to open said valve thereby to unlock said piston responsive toactuation of said one switch.

l 26, Micrometer apparatus comprising: supporting means; a motor on saidsupporting means, a sensing head mounted for reciprocation on saidsupporting means and 23 operatively connected to said motor, a sensingplunger mounted on said sensing `head for reciprocal movement relativethereto, two spaced apart switches mounted on said sensing head, saidplunger having an arm which eX- tends into the space between saidswitches, spring means urging said arm into a first position inengagement with one of said switches, said plunger having a portionadapted to engage a Work piece, said plunger being movable from saidtirst position into a second position with said arm in engagement withthe other of said switches responsive to engagement of said plunger withsaid work piece; means Ifor selectively actuating said motor thereby tomove said sensing head so that said plunger moves into said secondlposition; means coupling said other switch and said motor for lockingthe same and said 15 2,820,283

References Cited in the file of this Apatent UNITED STATES PATENTS pFleischli June 2,

1,918,528 Heischli June 18, `1933 2,086,667 Fletcher `uly 13,19372,544,522 Bertelensen Mar. 6, 1951 2,602,361 Meyer .I July 8, 19522,714,759 Wangenheim Aug. 9,v 19'55 Anderson J an. 21,

